Nitric oxide is one of neurotransmitters and is known to have vasodilatory action and memory enhancing action. For this reason, nitric oxide has been studied to apply to a drug for treating epilepsy or Alzheimer type dementia. Nitric oxide is also a central substance of action mechanism of nitroglycerin as a drug for angina pectoris and VIAGRA as a drug for erectile dysfunction.
In recent years, furoxan (1,2,5-oxadiazole-2-oxide) has attracted attention as a compound that releases nitric oxide under physiological conditions and is expected as a new medical lead compound (for example, see Non-Patent Literatures 1 and 2).
However, although the nitric oxide-releasing ability exhibited by the furoxan compound is largely dependent on the position and property of the substituent on the ring structure, only a limited number of methods for synthesizing the furoxan compound are known (see, for example, Patent Literature 1). Therefore, the types of substituents included in conventionally known furoxan compounds were limited.